In recent years, commercial laundry industry has confronted a variety of environmental challenges. A typical commercial laundry operation consumes various fabric-cleaning solvents and chemicals, which are becoming too costly for complying with ever-increasing environmental regulations. A “dry clean” process was invented in the mid-19th century and became a symbol of the commercial laundry industry. The dry clean process uses chemical agents instead of water and is effective in cleaning wool, silk, fur, and other fabric types which are difficult to clean with water. A first generation of dry cleaning methods generally used petrochemical solvents such as kerosene and even gasoline. Because kerosene and gasoline were found to be excessively flammable and outright dangerous for use in a commercial laundry facility, less flammable petrochemical agents such as a paraffin-derived “Stoddard solvent” were widely used until the 1950's.
The petrochemical solvents used in the first generation of dry cleaning were still frequently susceptible to fire and explosions, and a safer dry-cleaning solvent was need in the industry. Starting in the 1930's, tetrachloroethylene, also known as perchloroethylene or “perc” in short, was discovered to be a very effective and non-flammable dry-cleaning agent. Perc was also gentle to many sensitive garments such as silk and wool. The use of perc in dry cleaning became a defacto industry standard by the mid-20th century and still is a common choice for dry cleaning operations.
However, in the 1990's, tetrachloroethylene was declared to be a carcinogen against humans and a contaminating agent on the Earth's atmosphere. For example, in 1993, the California Air Resources Board devised an airborne toxic control measure to reduce perc emissions from commercial laundry facilities. Many commercial laundry facilities today face strict environmental standard restrictions and even a general phase-out of perc-based dry cleaning machines. Although more eco-friendly chemical agents such as glycol ethers and decamethylcyclopentasiloxane (D5) were devised, increasingly stringent environmental regulations against any chemical dry-cleaning agents and a high cost of operation and equipment have prevented the commercial laundry industry from rapidly adopting such eco-friendly alternatives.
An undesirable alternative to dry cleaning is simply a “wet clean” process, which agitates garments immersed in water with an injection of biodegrable detergents, similar to a modern household washing machine which uses water. Unfortunately, the wet clean process is very undesirable in a commercial laundry operation because only a limited number of fabric types can be treated with a wet-cleaning machine. Furthermore, even fabric types which can be washed with water experience an unacceptable level of shrinkage, wrinkling, and/or damage to garments in a high-volume commercial laundry operation. A laundry facility using water-based wet-cleaning machine inevitably spends an exorbitant amount of time for mitigating shrinkage and wrinkling of garments before a garment press machine can be used. Furthermore, the cost of a water-based wet cleaning machine tends to be even more expensive than a dry cleaning machine.
If a conventional dry-cleaning machine operator could repeatedly reuse perc or other dry-cleaning solvents without frequent replenishment, the operator's costs associated with raw materials and environmental regulations may be reduced dramatically. Furthermore, repeated reuse of already-used dry-cleaning solvents in commercial dry-cleaning operation may also reduce environmental contamination and damage associated with disposing perc and other harmful chemicals from commercial dry cleaning operations. Unfortunately, conventional dry-cleaning machines do not incorporate robust filtering agents or mechanisms to fully decontaminate or detoxify soiled dry-cleaning solvents. At best, conventional dry-cleaning machines only provide basic particulate filtering through an internal mesh filtering unit, which is generally insufficient for removing undesirable odors and contaminated substances from already-used dry-cleaning solvents.
Therefore, it may be desirable to devise a novel dry-cleaning solvent filter apparatus that provides robust decontamination, odor removal, and rejuvenation of dry-cleaning solvents to enable repeated reuse of such reclaimed solvents in commercial dry cleaning operations. Furthermore, it may also be desirable to devise a novel dry-cleaning solvent filter apparatus that can be externally connected to or internally incorporated into a conventional dry-cleaning machine with minimal design modifications to the conventional dry-cleaning machine itself for convenient before-market or aftermarket design integrations and installations.
In addition, it may also be desirable to devise a novel filtration agent comprising unique multi-metallic and multi-chemical compounds for robust decontamination of used dry-cleaning solvents in a novel dry-cleaning solvent filter apparatus. Moreover, it may also be desirable to devise a method of operating a novel dry-cleaning solvent filter apparatus to provide robust decontamination, odor removal, and rejuvenation of dry-cleaning solvents to enable repeated reuse of such reclaimed solvents in commercial dry cleaning operations.